Mechanical systems under heavy loads will deteriorate due to the frictional forces created by relatively moving, rubbing and bearing metal surfaces. Often, lubricants for such operations cannot prevent wear of the metal or reduce the coefficient of friction and, as a result, the system performance is affected. Often, antiwear additives, load carrying and friction modifying additives are blended with lubricants in order to prevent wear, reduce fuel consumption and increase the operating life of the machinery.
Lubricants such as lubricating oils and greases are known to undergo oxidative deterioration upon exposure to elevated temperatures. Oxidative deterioration causes an increase in the acidity and viscosity of the lubricant. Acidity causes corrosion of metal parts exposed to the lubricant and high viscosities cause the lubricant to thicken and lose its lubricating ability. These problems can eventually lead to mechanical failure. Antioxidants are incorporated into lubricants to prevent oxidation.
In U.S. Pat. No. 4,960,529 a reaction product of a diacyl halide, an amine and a phosphite is described as having antioxidant and antiwear properties in lubricants. The diacyl halide is derived from an aliphatic dicarboxylic acid, i.e. decanedicarboxylic acid and thionyl chloride.
U.S. Pat. No. 4,229,310 discloses a reaction product of a partially esterified alcohol with a phosphorus oxyhalide or a trihydrocarbyl phosphate. The reaction product is described as having improved demulsifying and antiwear properties in lubricants.
U.S. Pat. No. 4,234,435 discloses reacting a carboxylic acid acylating agent with a polyoxyalkylene polyamine to produce an acylated amine, which is further reacted with one or more reactants which include a sulfur chloride and a hydrocarbyl phosphite.
Alkenylsuccinic anhydrides are known for their lubricity and solubility properties in lubricants. Imide derivatives of alkenylsuccinic anhydrides have been known for their detergent and dispersancy properties.